Surgical clips and methods for tissue approximation

ABSTRACT

Surgical clips, and methods of use thereof, are provided for tissue approximation and attachment, and more particularly, for sealingly joining a graft vessel to a target vessel. The graft vessel has a free end and a graft vessel wall defining a graft lumen. The target vessel has a target vessel wall defining a target lumen and has an opening in the target vessel wall. The anastomosis clip includes a clip body having a distal extremity with a distal end and a proximal extremity with a proximal end. The distal end is configured to penetrate through the graft vessel wall near the free end and through the target vessel wall near the opening such that both the distal and proximal ends of the clip body are outside the graft and target vessels. At least a portion of the clip body is shapable so as to compress the graft vessel wall against the target vessel wall with the target vessel lumen in communication with the graft vessel lumen.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.10/196,847, filed Jul. 17, 2002, now abandoned, which is a continuationof U.S. patent application Ser. No. 09/855,070, filed May 15, 2001, nowissued as U.S. Pat. No. 6,461,365, which is a continuation of U.S.patent application Ser. No. 09/420,609, filed Oct. 18, 1999, now issuedas U.S. Pat. No. 6,254,615, which is a continuation of U.S. patentapplication Ser. No. 08/598,513, filed on Feb. 8, 1996, now issued asU.S. Pat. No. 5,976,159, which is a continuation-in-part of U.S. patentapplication Ser. No. 08/394,333, filed Feb. 24, 1995, now issued as U.S.Pat. No. 5,695,504, the complete disclosure of all of which is herebyincorporated herein by reference for all purposes.

FIELD OF THE INVENTION

The present invention relates generally to surgical instruments andmethods, and more specifically to devices and methods for surgical woundclosure, tissue approximation and attachment, and vascular anastomosis,especially coronary artery anastomosis.

BACKGROUND OF THE INVENTION

In coronary artery disease, one or more of the coronary arteries whichsupply oxygenated blood to the heart are partially or entirely blockedby a build-up of atherosclerotic plaque within the artery. This deprivesthe heart muscle of oxygen and nutrients, leading to myocardialinfarction and even death.

Coronary artery bypass grafting remains the gold standard for thesurgical treatment of severe coronary artery disease. In coronary arterybypass grafting, or CABG, a graft vessel is used to bypass a blockage ina coronary artery by connecting the distal end of the graft vessel tothe coronary artery downstream of the blockage and connecting theproximal end of the graft vessel to a source of arterial blood upstreamof the blockage. Various types of graft vessels may be used, including asaphenous vein taken from the patient's leg, a radial artery removedfrom the patient's forearm, or a prosthetic graft made of expandedpolytetrafluoroethylene, Dacron, or other suitable material.Additionally, the left or right internal mammary arteries, whichoriginate from the subclavian artery and reside on the top of the chestwall, may be resected at a distal location and left intact proximally,the free distal end then being connected to the diseased coronary arterydownstream of the blockage. Similarly, the gastroepiploic artery, whichoriginates from the gastroduodenal artery in the abdomen, may beresected at a distal location in the abdomen and passed into the thoraxthrough a puncture in the diaphragm for attachment to the diseasedcoronary artery. Other types of graft vessels may also be used, as wellas combinations of several different types of graft vessels in order tobypass multiple coronary blockages.

The surgical interconnection of two vascular structures, such as a graftvessel and a coronary artery, is a process known as anastomosis. InCABG, the anastomosis of a graft vessel to a coronary artery isparticularly challenging. Several factors contribute to this challenge.First, the scale of the vessels is extremely small, the coronaryarteries having a diameter on the order of about 1-5 mm, and the graftvessels having a diameter on the order of about 1-4 mm for an arterialgraft such as a mammary artery, or about 4-8 mm for a vein graft. Inaddition, the completed anastomosis must not only provide a sealedconnection and a patent blood flow path between the graft vessel and thecoronary artery, but must further provide a connection which minimizesthe exposure of the blood to foreign material or external vesselsurfaces which can cause thrombosis at the anastomosis site. Moreover,recent studies suggests that the anastomosis site should not bedramatically different in compliance relative to either the coronaryartery or the vascular graft, since such a “compliance mismatch” mayalso cause thrombus to form at the anastomosis.

Suturing is the technique of choice for coronary anastomosis in the vastmajority of CABG cases today. The anastomosis is performed by creating asmall opening, or arteriotomy, in the coronary artery, and passing aseries of running stitches through the walls of the graft vessel and thecoronary artery, respectively, around the perimeter of the arteriotomyso as to compress the end of the graft vessel against the side wall ofthe coronary artery. The surgeon has a great deal of flexibility inselecting the optimum location for each stitch, based on the shape,structure and condition of the two vessels. The suture needle may beplaced initially through the graft vessel wall, and, before the twovessels are closely approximated, the needle then independently placedthrough the desired location in the target vessel wall. The suture isthen tensioned to approximate the two vessels and create a tight,hemostatic seal. The sutured anastomosis thus offers a secure, sealedand patent connection between the two vessels, while having asubstantial degree of compliance due to the flexible nature of thesuture material.

A drawback of the sutured anastomosis is, however, the high degree ofskill, dexterity, and acute visualization required. In addition, thecompletion of the anastomosis takes a significant amount of time, duringwhich the patient is maintained under cardioplegic arrest andcardiopulmonary bypass. The period of cardioplegic arrest shouldgenerally be minimized in order to minimize damage to the heart muscle.Further, in recent years, some attempts have been made at reducing theinvasiveness and trauma of CABG surgery by working through smallerincisions or “ports” between the ribs and using endoscopic surgicaltechniques. Performing microvascular anastomoses with conventionalsutures is extremely difficulty when working through small ports,particularly if direct vision of the anastomosis site is not possibleand reliance upon endoscopic visualization techniques is necessitated.

Various ideas have been proposed for simplifying and accelerating theprocess of coronary anastomosis using sutureless anastomosis devices.For example, in U.S. Pat. No. 4,350,160 to Kolesov et al., a device isdisclosed for creating an end-to-end anastomosis by everting each vesselend over a split bushing and driving a plurality of staples through theeverted vessel ends. For coronary anastomosis, this device requires thatthe coronary artery be severed downstream of the blockage and thedownstream end dissected away from the surface of the heart in order toallow it to be connected end-to-end to the graft vessel. This adds anundesirable increase in time, difficulty and risk to the procedure. Inaddition, the staples in the Kolesov device are always positioned in afixed pattern, allowing no flexibility in selecting the location inwhich each staple is to be driven through the vessels.

In U.S. Pat. No. 4,624,257 to Berggren et al., a device is disclosed forcreating either end-to-end or end-to-side anastomoses. The deviceconsists of a pair of rigid rings each having a central opening throughwhich the end of the coronary or graft vessel may be drawn through andeverted over the ring. A set of sharp pins extend outwardly from theface of each ring and pierce through the vessel wall to maintain thevessel in the everted configuration. The rings are then joined togetherto align the end of the graft vessel with the opening in the targetvessel. While this device may be suitable for end-to-side anastomosis,eliminating the need to sever and isolate a free end of the coronaryartery, the device requires that the side wall of the coronary artery beeverted through the central opening of the ring, a maneuver which islikely to be extremely difficult in coronary anastomosis due to thestructure and size of the coronary arteries. Moreover, the use of rigidrings that completely encircle the graft vessel and the arteriotomycreates a severe compliance mismatch at the anastomosis site which couldlead to thrombosis.

An additional device which has been proposed for end-to-side anastomosisis seen in U.S. Pat. No. 5,234,447 to Kaster et al. This device consistsof a rigid ring having a plurality of pointed legs extending from thering axially in the distal direction and a plurality of angled legsextending axially from the ring in the proximal direction. The graftvessel is placed through the middle of the ring and the end is evertedover the pointed legs, which puncture the vessel wall and retain it onthe ring. The pointed legs are then bent outwardly, and the everted endof the graft vessel and the outwardly-oriented pointed legs are insertedthrough an arteriotomy in the target vessel so that the pointed legsengage the interior wall of the target vessel. The angled legs on theproximal end of the ring are then bent toward the target vessel topenetrate the outer wall thereof. While the Kaster device has a simpleone-piece design and avoids the need to evert the wall of the targetvessel over the device as proposed in Berggren, the device maintains arigid ring structure which results in inadequate compliance at theanastomosis. In addition, the rigidity of Kaster's device leaves thesurgeon little flexibility in selecting the optimum location where eachleg of the device should be driven into the graft and target vessels, incontrast to the flexibility available when placing suture stitches.

U.S. Pat. No. 4,586,503 to Kirsch et al. discloses an alternative schemefor creating microvascular anastomoses. The Kirsch device consists of aplurality of individual clips each consisting of a pair of arcuate legsinterconnected by a bridging section. The edges of the vascular tissueto be anastomosed are approximated and everted outwardly so that a clipcan be placed over the tissue edges, and the clip is then crimped topermanently deform the legs in an inward position. The clip therebyretains the edges of the tissue together without puncturing the tissue.A plurality of clips are placed around the graft vessel in this mannerto accomplish the anastomosis. The Kirsch device eliminates thecompliance problems of rigid ring-type devices, and allows the surgeonthe flexibility to select the optimum location for the placement of eachclip. However, the Kirsch clips suffer from several disadvantages. Forexample, placement of the clips while maintaining eversion andapproximation of the tissue edges is difficult and time-consuming.Typically, two pairs of forceps are needed to hold the tissue edges inapproximation while a third hand applies the clip, in contrast tosuturing, where only one tissue edge needs to be held at one time whilethe suture needle is driven through it. The Kirsch clips are especiallyawkward in endoscopic applications, where access, visualization, andmaneuverability of instruments are limited. Moreover, in end-to-sideanastomosis, the tissue edges along the arteriotomy must be evertedoutwardly and approximated with the everted end of the graft vessel, amaneuver which becomes increasingly difficult as the ends of thearteriotomy are approached. In addition, due to variation in vessel sizeand structure, variation in the crimping force applied, and otherfactors, the clips may not reliably maintain the anastomotic connection.

In view of the foregoing, devices and methods are needed whichfacilitate the performance of vascular anastomosis, especially coronaryanastomosis, but which eliminate the various drawbacks of prior devices.The devices and methods should allow the surgeon to select the specificlocations on the graft and target vessels where the device is to beapplied, similar to selecting the location of each stitch in a suturedanastomosis. The devices and methods should be relatively simple toutilize without requiring an undue degree of skill and dexterity, evenat the small scale of the coronary arteries, and even in endoscopicapplications. The devices and methods should be useful for performingend-to-side, end-to-end and side-to-side anastomoses. Further, thedevices and methods should produce an anastomosis which is reliablysealed and patent, with a degree of compliance comparable to suturedanastomosis.

SUMMARY OF THE INVENTION

The invention provides surgical clips and methods that meet theforegoing needs, and that are useful not only for coronary anastomosis,but for anastomosis of a variety of other vascular structures, as wellas in ligation, wound closure and other tissue approximation andattachment applications. The invention offers a simple and convenientsolution to coronary anastomosis, allowing the anastomosis to beperformed using only two hands more quickly and easily than existingdevices, but with the hemostasis, patency, compliance and reliability ofsutures. The devices and methods of the invention are useful not only inconventional open surgical procedures, but in endoscopic, laparoscopic,thoracoscopic and other minimally-invasive procedures as well.

In a first embodiment of the invention, a surgical clip is provided forapproximating or attaching a first tissue layer to a second tissuelayer. The first and second tissue layers may be any of various tissuestructures, such as flaps of tissue adjacent to a wound or incision in avessel, organ or body wall, but the invention is particularly suitablefor vascular anastomosis, wherein a graft vessel is joined to a targetvessel. The graft vessel has a free end and a graft vessel wall defininga graft lumen. The target vessel has a target vessel wall defining atarget lumen and has an opening in the target vessel wall, which may bean incision or other opening formed in the target vessel wall (forend-to-side or side-to-side anastomoses), or an opening at a free end ofthe target vessel (for end-to-end anastomoses). The surgical clipincludes a clip body having a distal extremity with a distal end and aproximal extremity with a proximal end. The distal end is configured topenetrate through the graft vessel wall near the free end and throughthe target vessel wall near the opening such that both the distal andproximal ends of the clip body are outside the graft and target vessels.At least a portion of the clip body is shapable so as to compress thegraft vessel wall against the target vessel wall with the target vessellumen in communication with the graft vessel lumen.

By penetrating the graft and target vessel walls, the surgical clipprovides the long-term reliability of a sutured connection. In addition,maintaining both ends of the clip outside of both the graft and targetvessels minimizes the amount of foreign material contacting blood,eliminates the need for an internal anvil which must be removed afterclip application, facilitates visual confirmation of successfulapplication of the clip, and permits manipulation of the ends of theclip to re-apply, reposition or remove the clip. Further, the surgicalclip provides a reliable hemostatic seal by having a deformable portionwhich compresses the graft vessel wall against the target vessel wall.Moreover, through the use of a plurality of individual surgical clips,the invention provides the surgeon with the flexibility to select theideal location on both the target and graft vessel walls to which eachclip should be applied, depending upon vessel structure, condition andshape. The use of multiple independent clips also produces ananastomotic connection having compliance comparable to a suturedanastomosis.

The surgical clip may have a variety of configurations. The clip bodywill generally have an outer surface against which the graft and targetvessel walls are compressed. In one embodiment, the proximal extremitycomprises a leg extending from the clip body that is movable between anopen position spaced apart from the distal extremity and a closedposition closer to the distal extremity. The proximal extremity has aninner surface which faces the outer surface of the clip body in theclosed position. The clip body is thus “shaped” by moving the proximalextremity into the closed position, thereby compressing the graft andtarget vessel walls between the inner and outer surfaces. The proximalextremity may be hingedly coupled to the clip body to facilitatemovement thereof, but is preferably configured to be inelasticallydeformed from the open into the closed position.

The movable proximal extremity may also be configured to contact or toextend across the distal extremity in the closed position. In oneconfiguration, the proximal extremity has an end portion which includestwo generally parallel segments which extend across the distal extremityin the closed position and a slot between the parallel segments forreceiving the distal extremity. The proximal extremity may also beconfigured to shield the distal end of the distal extremity in theclosed position to prevent inadvertent injury to tissue. Preferably, theproximal extremity is configured to prevent its passage through thegraft and target vessel walls. For example, the proximal extremity mayhave a cross-sectional area which is substantially larger than that ofthe distal extremity so that it cannot pass through the puncture createdby the distal extremity. The proximal extremity may also be oriented atan angle, usually at least about 90°, relative to the distal extremityto inhibit its passage through the vessel walls.

In another embodiment, the distal extremity is movable between an openposition spaced apart from the proximal extremity and a closed positioncloser to the proximal extremity, and the distal extremity has an innersurface which compresses the graft and target vessel walls against theouter surface of the clip body in the closed position. Preferably, thedistal extremity is inelastically deformable into the closed position.

The distal extremity is preferably oriented such that its inner surfaceis at an angle of at most about 90° relative to the outer surface of theclip body. The inner surface (or the entire distal extremity) may alsobe arcuate in shape. The distal extremity is usually tapered to a sharppoint at its distal end to facilitate penetration of the graft andtarget vessel walls. One or more barbs may be provided near the distalend to maintain the graft and target vessel walls on the distalextremity.

The invention also provides an applier for applying the surgical clip.The applier includes a holding mechanism for releasably holding asurgical clip and a shaping mechanism for shaping the clip so as tocompress the graft vessel wall against the target vessel wall. Althougha variety of holding mechanisms are possible, in one embodiment theholding mechanism comprises a pin at the distal end of the applier, inwhich case the surgical clip includes a middle portion having anaperture for receiving the pin. Various types of shaping mechanisms arealso possible, but in an exemplary configuration, the clip applierincludes an inner shaft and an outer shaft axially movable with respectto each other. The clip is held by a first of the inner and outershafts, and the clip body is shaped by engagement with a second of theinner and outer shafts. In a particularly preferred aspect, the clipapplier is configured for endoscopic, laparoscopic, thoracoscopic, orother minimally-invasive procedures, by holding the clip at the end of asmall-profile elongated shaft suitable for positioning through a smallincision, trocar sleeve, tubular port, cannula or the like. An actuatorat the proximal end of the shaft permits remote application of the clipfrom outside the body cavity.

In another embodiment, the surgical clip of the invention comprises aclip body, a needle portion extending from the clip body that has adistal end configured to penetrated the graft and target vessel wallsand to extend outside of the graft and target vessels. The clip body isconfigured to prevent its passage through the graft and target vesselwalls so that it remains outside of the graft and target vessels. Aretainer is further provided on the clip for retaining the graft andtarget vessel walls on the needle portion.

In one configuration, the retainer comprises a leg attached to the clipbody and movable from an open position spaced apart from the needleportion to a closed position closer to the needle portion. The leg maybe hingedly movable or inelastically deformable into the closedposition. Preferably, the retainer is configured to compress the graftvessel wall against the target vessel wall for reliable hemostasis. Theleg may also be configured to shield the distal end of the needleportion in the closed position.

Alternatively, the retainer may comprise a barb or other retentiondevice on the needle portion itself. A plurality of barbs may beprovided at spaced apart positions along the extremity of the needleportion so that the needle portion may be passed through the graft andtarget vessel walls a desired amount and the barbs will prevent theneedle portion from backing out of the vessel walls. As an alternativeto barbs, a retainer which is unidirectionally slidable or threadableonto the needle portion may be provided which is placed on the needleportion after it has been passed through the graft and target vesselwalls. The needle portion is preferably hook-shaped, J-shaped ororiented at an angle of at least about 90° relative to the clip body sothat the needle portion may be advanced through the vessel walls untilits curved portion or the clip body engages the vessel wall. The barbsor other retaining devices are positioned relative to the clip body soas to maintain the graft vessel wall in compression against the targetvessel wall.

In an additional embodiment, the surgical clips of the invention areconfigured to be coupled to a flexible ring-shaped band, which ispreferably a continuous ring of suture, metal or plastic wire or strip,or other flexible material. The band defines a central opening throughwhich the graft vessel may be received. Each clip has a first portionfor engaging the graft vessel wall, and a second portion for engagingthe target vessel wall, the first and second portions being configuredto retain the graft vessel wall in sealing engagement with the targetvessel wall. A plurality of clips are positionable at spaced-apartlocations around the band. In this way, application of the clips to thevessels is accomplished by simply placing the band over the end of thegraft vessel and applying each clip to the vessel wall. The graft vesselmay then be positioned adjacent to the opening in the target vessel andeach clip applied to the target vessel wall to create a sealedanastomotic connection. The band may be either left in place, orconfigured for removal by cutting or other wise detaching the ring fromthe clips.

Preferably, the clips are coupled to the band so as to be slidable tothe desired position around the perimeter of the band. In oneconfiguration, the clips have a loop or eyelet through which the bandmay be slidably received. The clips in this embodiment may have any ofvarious configurations suitable for vascular anastomosis, includingthose described above, as well as other configurations not specificallydescribed.

In a preferred embodiment, a method of joining a graft vessel to atarget vessel according to the invention comprises providing a pluralityof surgical clips each including a clip body having a distal extremitywith a distal end and a proximal extremity with a proximal end;penetrating the graft vessel wall and the target vessel wall with thedistal extremity of each surgical clip such that the distal and proximalends are disposed outside of the graft and target vessels; and shaping aportion of each clip body outside of the graft and target vessels so asto compress the graft vessel wall against the target vessel wall withthe graft lumen in communication with the target lumen. In this way, arobust, reliable and hemostatic anastomosis is provided which is simpleand convenient to perform using only two hands, which minimizes theamount of foreign material in contact with the blood stream, whichallows the surgeon to place each clip in the optimum location based onthe size, shape and condition of the vessels, and which provides adegree of compliance in the completed anastomosis comparable to that ofsutured anastomoses. The invention thus combines the ease ofapplication, flexibility of position, reliability, and compliance ofsutures, with the convenience and quickness of surgical clips.

Because of its simplicity and convenience, the invention is particularlywell-adapted for use in endoscopic, laparoscopic, thoracoscopic andother minimally-invasive applications. The clips may be applied to abody structure using slender instruments positioned through percutaneousports such as trocar sleeves, tubular cannulas, or small incisions,under direct visualization through such ports or under video-basedvisualization by means of an endoscope positioned through a port.

The nature and advantages of the invention will become more apparentfrom the following detailed description taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A-1B are front elevational views of a surgical clip constructed inaccordance with the principles of the invention in an open and a closedposition, respectively.

FIGS. 2A and 2B are front and top cross-sectional views, respectively,of a clip applier for applying the surgical clip of FIGS. 1A-1B in anopen position.

FIG. 2C is a front cross-sectional view of the clip applier of FIG. 2Ain a closed position.

FIGS. 3A-3B are side cross-sectional views of a distal portion of theclip applier of FIGS. 2A-2C in open and closed positions, respectively,illustrating the application of the surgical clip to two portions oftissue.

FIG. 4 is a perspective view of a distal portion of the clip applier ofFIGS. 2A-2C schematically illustrating the use of the surgical clip inthe anastomosis of a graft vessel to a target vessel.

FIGS. 5A and 5C are front elevational views of a second embodiment of asurgical clip constructed in accordance with the principles of theinvention in an open and a closed position, respectively.

FIG. 5B is a top view of the surgical clip of FIG. 5A in a straightenedconfiguration.

FIGS. 6A-6B are side cross-sectional views of a distal portion of a clipapplier in open and closed positions, respectively, illustrating theapplication of the surgical clip of FIGS. 5A-5C to two portions oftissue.

FIGS. 7A-7B are front elevational views of a third embodiment of asurgical clip constructed in accordance with the principles of theinvention in an open and a closed position, respectively.

FIGS. 8A-8B are side cross-sectional views of a distal portion of a clipapplier in open and closed positions, respectively, illustrating theapplication of the surgical clip of FIGS. 7A-7B to two portions oftissue.

FIGS. 9A-9B are front elevational views of a fourth embodiment of asurgical clip constructed in accordance with the principles of theinvention in an open and a closed position, respectively.

FIGS. 10A-10D are side cross-sectional views of a distal portion of aclip applier in four successive configurations, illustrating the closureof the surgical clip of FIGS. 9A-9B.

FIGS. 11A-11B are perspective views of two embodiments of an anastomosisclip system constructed in accordance with the principles of theinvention.

FIGS. 12A-12F are front views of various embodiments of anastomosisclips useful in the anastomosis clip system of FIGS. 11A-11B.

FIG. 12G is a front view of the anastomosis clip of FIG. 12F in a closedposition.

FIGS. 13A-13C are perspective views of the anastomosis clip system ofFIG. 11A schematically illustrating the use of the anastomosis clipsystem for the anastomosis of a graft vessel to a target vessel.

FIGS. 14A and 14C are front views of a further embodiment of a surgicalclip according to the invention in an open and a closed position,respectively.

FIG. 14B is a top view of the surgical clip of FIG. 14A in astraightened configuration.

FIG. 15A is a side cross-sectional view of a clip applier for applyingthe surgical clip of FIGS. 14A-14C.

FIGS. 15B-15C are side cross-sectional and top views, respectively, of adistal portion of the clip applier of FIG. 15A.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

A first embodiment of a surgical clip according to the invention isillustrated in FIGS. 1A-1B. Surgical clip 20 comprises a clip body 22, adistal extremity 24 attached to a first end of clip body 22 and aproximal extremity 26 attached to a second end of clip body 22. Distalextremity 24 has a sharp distal point 28 configured to penetrate one ormore layers of tissue such as a wall of a vessel, and is sufficientlyrigid to allow the distal extremity to be driven through such tissuewithout bending or buckling. Distal extremity 24 may be straight,angled, or arcuate, and may include barbs or other means of retention,as further described below. The distal extremity will have a lengthsufficient to pass through the combined thickness of all tissue layersto be fastened together using clip 20, preferably about twice thecombined thickness of the tissue layers, e.g. about 2-5 mm for coronaryanastomosis applications, or larger for application to thicker tissuessuch as the aorta, heart wall, intestines, bowel, or fascia.

Proximal extremity 26 is movable between an open position in which it isspaced-apart from distal extremity 24 as shown in FIG. 1A, and a closedposition in which it is closer to distal extremity 24, as shown in FIG.1B. Proximal extremity 26 may be movably attached to clip body 22 invarious ways, including by a pivot pin, living hinge or the like, but,in a preferred embodiment, is attached by a deformable leg 30, usuallyconstructed of an inelastically deformable metal so that once it isplaced in the closed position, proximal extremity 26 will not return tothe open position without similar deformation. If a hinge arrangement isused, a latch (not shown) may be provided on clip body 22 to engage andmaintain the proximal extremity in the closed position. Proximalextremity 26 has an inner surface 32 which faces an outer surface 34 ofclip body 22 in the closed position. In the open position, inner surface32 is disposed sufficiently apart from outer surface 34 to facilitateplacement of distal extremity 24 through the tissue layers withoutinterference, usually being at an angle of at least about 45°, usuallyabout 60°-120°, and preferably about 90°, relative to outer surface 34.In the open position, clip 20 thus forms a general C-shape or U-shape,with a gap between the distal and proximal extremities. The size of thegap will depend upon the size and nature of the tissue to which clip 20is to be applied, with the distance between distal extremity 24 andproximal extremity 26 usually ranging from about 0.5-8.0 mm, moreparticularly about 1.0-5.0 mm, and preferably, in coronary applications,about 1.5-3.0 mm.

In the closed position, inner surface 32 is preferably separated fromouter surface 34 by a distance of less than about the combined thicknessof the tissue layers to be fastened together with clip 20. In this way,the tissue layers will be compressed against one another betweenproximal extremity 26 and clip body 22, providing important advantages,as described in more detail below. The amount of tissue compression willdepend upon the nature of the tissue, the need for a fluid seal, theinternal pressures of any fluid within the tissue, and other factors,but will usually compress the tissue layers so as to reduce theircombined thickness by at least about 10%, and preferably about 30%-50%from their combined, uncompressed thickness. In an exemplary embodimentsuitable for coronary anastomosis, inner surface 32 is separated fromouter surface 34 by a distance of no more than about 0.02-1.0 mm, andpreferably 0.05-0.3 mm, at the closest point between the two surfaceswhich contact the tissue layers. In other applications involving thickertissues this distance will be greater, as needed to apply suitablecompressive force to the tissues without unnecessarily cutting, crushingor otherwise damaging the tissues.

Proximal extremity 26 is preferably configured to shield distal point 28of distal extremity 24 in the closed position to avoid the possibilityof the distal point causing inadvertent injury to tissue. In oneconfiguration, proximal extremity 26 has an outer side 36 which has alength generally equal to that of distal extremity 24 so that the upperend 38 of outer side 36 is aligned with distal point 28 in the closedposition. Outer side 36 further has a shape selected to match that ofdistal extremity 24, having an arc generally matching that of the innerside of distal extremity 24 in the embodiment of FIG. 1. In otherconfigurations, proximal extremity 26 may include a slot, channel oraperture along outer side 36 which receives all or a portion distalextremity 24 in the closed position, or a separate sleeve or cap (notillustrated) may be placed over distal point 28.

Clip body 22 includes a means by which clip 20 may be held by a clipapplier or other instrument for applying the clip to body tissue. In theembodiment of FIGS. 1A-1B, the clip holding means comprises an aperture40 which extends through the clip body in a direction generally parallelto the axis of movement of proximal extremity 26. Aperture 40 may havevarious shapes and may, instead of a single aperture, include two ormore separate apertures, depending upon the type of clip applier to beused.

FIGS. 2A-2C illustrate a clip applier 42 suitable for applying surgicalclip 20 of FIGS. 1A-1B. Clip applier 42 has an outer shaft 44 having adistal end 46, a proximal end 48, and a lumen 50. An inner shaft 52 isslidably disposed within lumen 50. Inner shaft 52 has a clip holdingmechanism 54 at its distal end which includes two transverse pins 56(better seen in FIGS. 3A-3B) that are received within aperture 40 ofclip 20. Clip 20 is held so that distal extremity 24 and proximalextremity 26 extend generally radially outward from the longitudinalaxis of inner shaft 52. As shown in the top view of FIG. 2B, a clipcover 55 is slidably mounted within outer shaft 44 parallel to a distalportion of inner shaft 52. A spring 57 disposed around inner shaft 52within lumen 50 engages a proximal end of clip cover 55 and biases it ina distal direction. In this way, clip cover 55 may be retracted in theproximal direction to place a clip 20 on pins 56 as in FIG. 2A, thenreturned to the distal position of FIG. 2B so as to retain clip 20 onpins 56 as the clip is applied. Clip cover 55 has a cut-out 58 at itsdistal end to expose distal extremity 24 of clip 20 to facilitatepenetrating tissue with the distal extremity.

An actuator handle 60 includes a pair of leaves 62 having proximal ends64 pivotally attached to the proximal end of inner shaft 52 so thatactuator handle 60 remains a fixed distance from surgical clip 20whether open or closed. A link 66 is pinned at one end to each leaf 62and at its other end to a collar 67 attached to the proximal end 48 ofouter shaft 44. In this way, pivoting leaves 62 inwardly translatesouter shaft 44 distally relative to inner shaft 52 from the openposition of FIG. 2A to the closed position of FIG. 2C, thereby closingsurgical clip 20. A leaf spring (not shown) engages the inner sides ofeach leaf 62 to bias the leaves outward into the position of FIG. 2A.Alternatively, a tension or compression spring may be mounted aroundinner shaft 52 so as to engage the proximal end of outer shaft 44 andbias it proximally.

While clip applier 42 is illustrated in a single-fire design capable ofholding only one clip at a time, those of ordinary skill in the art willunderstand that the clip applier of the invention may be designed tohold multiple clips which can be applied repeatedly without manuallyreloading a clip into the applier after each application. For example,pins 56 could be configured to allow multiple clips to be stacked inparallel, with outer shaft 44 being designed to engage and close onlythe outer-most clip in the stack. Alternatively, clips 20 could be linedup serially in an axial channel within outer shaft 44 and a pusher couldexert a distal force against the proximal end of the line. The pusherwould feed clips 20 one-by-one onto pins 56 or other suitable clipholding means after each clip is closed.

Clip applier 42 preferably is configured for use in thoracoscopic,laparoscopic, or other endoscopic surgical procedures, wherein clipholding mechanism 54 and a distal portion of outer shaft 44 and innershaft 52 are positioned through a trocar sleeve, cannula, port or smallincision in the body wall, preferably between the ribs if operating inthe thoracic cavity. The distal portion of the clip applier musttherefore have a small profile so as to fit through a small accesspassage, and a sufficient length to reach the surgical site within thebody cavity. In an exemplary embodiment, the outer diameter of outershaft 44 and the largest transverse dimension of clip holding mechanism54 are less than about 12 mm, preferably less than about 10 mm, andouter shaft 44 has a length of at least about 10 cm, preferably at leastabout 20 cm.

FIGS. 3A-3B illustrate a distal portion of clip applier 42 in the openand closed positions, respectively. Two layers G, T of tissue to befastened together are penetrated with distal point 28 of clip 20 so thatthe edges of the tissue are disposed within the gap between distalextremity 24 and proximal extremity 24. Actuator handle 60 of clipapplier 42 is then actuated by pivoting leaves 62 inwardly, translatingouter shaft 44 distally relative to inner shaft 52. Distal end 46 of theouter shaft engages the proximal side of proximal extremity 26 anddeforms it into the closed position of FIG. 3B. The edges of tissuelayers G, T are thereby compressed between proximal extremity 26 andclip body 22. Leaves 62 contact each other and/or outer shaft 44 in theclosed position, preventing translation of outer shaft 44 beyond thatnecessary to close clip 20 with the desired degree of compression toavoid excessive crushing of tissue layers G, T. This compression oftissue is particularly advantageous when using clip 20 to performanastomosis of two vessels such as arteries. Such compression not onlyaccelerates the growing together of the two vessels, but creates animmediately hemostatic seal at the anastomosis site.

The performance of vascular anastomosis using clip applier 42 and clip20 is illustrated in FIG. 4, which shows a graft vessel G beinganastomosed to a target vessel T. Graft vessel G may be any of a varietyof vascular structures, including blood vessels, intestines, bowel andother body ducts. The invention is particularly useful, however, foranastomosis of small blood vessel such as the coronary arteries and theconduits commonly used in coronary artery bypass grafting (CABG),including internal mammary arteries, saphenous vein grafts, radialartery grafts, gastroepiploic arteries, and other natural and artificialvascular grafts. The invention may be used either for “proximal”anastomosis—that is, the connection of the upstream end of a graft to asource of blood such as the aorta—or “distal” anastomosis, theconnection of the downstream end of the graft to a coronary artery belowa blockage in the artery. Thus, in the context of coronary anastomosis,the term “graft vessel” is used herein to mean the vascular graft usedto provide a new conduit to a coronary artery, while “target vessel” isused to mean either the arterial blood source vessel (e.g. aorta) or thecoronary artery to which the “graft vessel” is connected. In otherapplications, “graft vessel” and “target vessel” may simply refer to thetwo vessels, organs or other structures which are being connectedtogether. In addition, while FIG. 4 illustrates an end-to-sideanastomosis as is common in CABG surgery, the clips and appliers of theinvention are useful in forming end-to-end and side-to-side anastomosesas well.

As shown in FIG. 4, an end GE of graft vessel G is connected to a sidewall TW of target vessel T around an opening O formed in wall TW by asurgical knife, scissors or other suitable instrument. In an artery suchas a coronary artery, opening O is known as an arteriotomy. Initially,either inside or outside the body cavity, one or more clips 20 may beattached to graft vessel end GE by puncturing distal point 28 throughthe graft vessel wall from the exterior side toward the interior side.Usually, this will be done with clip 20 held at the distal end of clipapplier 42, which is then positioned adjacent to the opening O in targetvessel T. Distal point 28 is then penetrated through target vessel wallTW from the interior of the vessel outward such that the distal edge ofgraft vessel end GE is approximated with the edge of opening O. This mayrequire slight pursing up of target vessel walls TW around the openingand/or slight flaring or eversion of graft vessel end GE, which isaccomplished using surgical forceps or other suitable instruments.Distal extremity 24 is passed through the graft and target vessel wallsuntil clip body 22 is contacting the wall of graft vessel G. Actuatorhandle 60 of clip applier 42 is then actuated so that outer shaft 44 isadvanced distally, deforming proximal extremity 26 into the closedposition of clip 20′. Clip applier 42 is then removed by withdrawingpins 56 from aperture 40. A plurality of clips 20, usually at leastabout 4, preferably 6-30, depending upon vessel size, the need for afluid seal, the internal pressures in the vessels, and other factors,are applied around the perimeter of opening O in this way until a sealedand secure anastomosis has been achieved.

It may be seen that the graft and target vessel walls are compressedbetween proximal extremity 26′ and clip body 22′, providing a secure andhemostatic connection. Distal point 28′ is safely shielded by proximalextremity 26′ to prevent interference or injury to surrounding tissue.Eventually, graft vessel G and target vessel T will grow together at theanastomosis. However, clips 20, being made of a biocompatible materialsuch as stainless steel, titanium or titanium alloy, tantalum, elgiloy,MP35N, or cobalt chromium-nickel alloy, may be left in the bodyindefinitely to ensure that the anastomosis remains intact.

An additional embodiment of a surgical clip according to the inventionis illustrated in FIGS. 5A-5C. Surgical clip 70 includes a clip body 72,a distal extremity 74 and a proximal extremity 76. Distal extremity 74has a sharp distal point 78 adapted to penetrate tissue. Clip body 72has an aperture 80 for receiving pins 56 on clip applier 42. Proximalextremity 76 has an end portion 82 adapted to overlap or cross-overdistal extremity 74 in the closed position shown in FIG. 5C. Asillustrated in FIG. 5B, showing a top view of clip 70 in a flattenedconfiguration, end portion 82 has a bifurcated construction with a pairof parallel segments 84 separated by a space 86. Segments 84 areseparated by a distance of at least the transverse width (or diameter,if round) of distal extremity 72 to allow distal extremity 74 to bereceived within space 86 in the closed position of FIG. 5C. Proximalextremity 76 is movable between the open position of FIG. 5A and theclosed position of FIG. 5C, preferably being constructed of abiocompatible metal or other deformable material so that the proximalextremity may be inelastically deformed into the closed position.Alternatively, proximal extremity 76 may be hingedly coupled to clipbody 72 and end portion 82 may be provided with a catch (not shown)which engages distal extremity 74 in the closed position. Clip 70 mayalso be constructed of a thermally responsive shape memory alloy such asNitinol (Raychem Corp.), whereby, once distal extremity 74 has beenapplied to the target tissue, heat may be applied to clip 70 usingheated forceps or other heat-tipped probe (or by heating the distal endof the clip applier itself) so as to raise the proximal extremity to atransition temperature in which it resumes the closed position of FIG.5C.

In order to facilitate closure of clip 70 in a repeatable andpredictable hinge-like manner, a notch 87 may be provided on the innersurface of proximal extremity 76 at the junction of the proximalextremity and clip body 72. When a distally directed force is applied toend portion 82 using clip applier 42 (described below), proximalextremity 76 tends to buckle at notch 87, allowing the proximalextremity to rotate about an axis passing generally through the notchwithout excessive deformation of the proximal extremity.

Clip 70, as with clip 20 above, is constructed so as to compress thetissue layers to which the clip is applied between proximal extremity 76and clip body 72. Proximal extremity 76 has an inner surface 88 whichfaces an outer surface 90 of clip body 72 in the closed position. Theclip is preferably configured so that, in the closed position of FIG.5C, inner surface 88 is separated from outer surface 90 adjacent todistal extremity 74 by a distance of less than the combined thickness ofall the tissue layers to which the clip is being applied, preferablyabout 0.05-0.3 mm for coronary distal anastomosis.

The closure of clip 70 by means of a clip applier 92 is illustrated inFIGS. 6A-6B. Clip applier 92 may be constructed similarly to clipapplier 42 of FIGS. 2-3, having an outer shaft 94 with a lumen 96extending through it, and an inner shaft 98 within lumen 94 over whichouter shaft 94 is axially slidable. The proximal portion of the clipapplier, not shown in FIGS. 6A-6B, may be constructed like that of clipapplier 42, with an actuator handle configured to translate outer shaft94 distally when actuated. A clip holding mechanism 100 is mounted tothe distal end of inner shaft 98, and includes a pair of transverse pins102 configured to extend through aperture 80 in clip 70. Clip 70 is thusheld in an orientation in which distal extremity 74 is disposedtransverse to, preferably about orthogonal to, the longitudinal axis ofinner shaft 98. A movable clip cover (not shown) like clip cover 55 ofFIGS. 2-3 may also be provided at the distal end of inner shaft 98 toretain clip 70 on pins 102. Proximal extremity 76 is disposed so thatthe curved outer surface of its end portion 82 is engaged by the distalend of outer shaft 94 when the outer shaft is advanced distally. Thedistal end of outer shaft 94 may be shaped so as to smoothly andcompletely deform proximal extremity 76 into the closed position of FIG.6B, including, for example, an annular undercut 104.

In use, a clip 70 is placed on pins 102 and the clip cover is allowed toslide distally over clip body 72 to retain it on the applier. Distalpoint 78 on clip 70 is penetrated through the tissue layers T, G towhich the clip is to be applied as shown in FIG. 6A. The actuator handleis then actuated, advancing outer shaft 94 distally over inner shaft 98to engage end portion 82 of clip 70 and deform it into the closedposition shown in FIG. 6B. The bifurcated end of end portion 82 crossesover distal extremity 78, completely enclosing tissue layers T, G.Advantageously, tissue layers T, G, are compressed between end portion82 and clip body 72, creating a secure and fluid-tight connection.

FIGS. 7A-7B illustrate an additional embodiment of a surgical clipaccording to the invention. Clip 110 includes a clip body 112, a distalextremity 114 and a proximal extremity 116. As in previous embodiments,distal extension 114 has a sharp distal point 118 configured topenetrate tissue. Proximal extremity 116 has an aperture 120 whichfacilitates holding the clip in a clip applier as described below.Proximal extremity 116 is movable relative to clip body 112 between anopen position spaced apart from distal extremity 114 and a closedposition closer to distal extremity 114, shown in FIG. 7B. Preferably,the proximal extremity is made of a deformable metal which may beinelastically deformed into the closed position. Proximal extremity 116has an inner surface 122 which faces an outer surface 124 of clip body112 in the closed position. Adjacent to the base of distal extremity114, inner surface 122 is preferably spaced apart from outer surface 124in the closed position by no more than the combined thickness of alltissue layers to which the clip is to be applied so as to compress thetissue therebetween. Proximal extremity 116 also has an outer side 126which is configured to shield distal point 118, preferably having ashape and dimension substantially the same as that of distal extremity114 so that outer side 126 lies adjacent and parallel to a substantialportion of distal extremity 114 in the closed position. Clip body 112has a proximal side 127 which facilitates closure of the clip, asdescribed below.

The use of clip 110 with a clip applier 128 is illustrated in FIGS.8A-8B. Clip applier 128 may have a construction like that of clipapplier 42 of FIGS. 2-3, having an outer shaft 130 with a lumen 132extending through it, and an inner shaft 134 disposed within lumen 132over which outer shaft 130 is slidable. An actuator handle (not shown)like that shown in FIGS. 2A-2C is provided at the proximal end of innershaft 134 and is coupled to outer shaft 130 such that actuation of thehandle translates outer shaft 130 distally. A clip holding mechanism 136is fixed to the distal end of inner shaft 134 and includes a recessedarea 138 configured to receive proximal extremity 116 of clip 110, and atransverse pin 140 configured to extend through aperture 120. A shelf142 along an inner edge of recessed area 138 prevents rotation of clip110 about pin 140. In this way, clip 110 is held with distal extremity114 extending generally in the radial direction from the longitudinalaxis of inner shaft 134. A clip cover 144 is slidably mounted withinlumen 132 parallel to a distal portion of inner shaft 134 and is movablefrom a proximal position shown in FIGS. 8A-8B to a distal position inwhich the clip cover extends over proximal extremity 116 of clip 110 toretain it on pin 140. A spring 146 within lumen 132 engages the proximalend of clip cover 144 and biases it into the distal position.

When the actuator handle of clip applier 128 is actuated, outer shaft130 is advanced distally so that its distal end engages proximal side127 of clip 110, thereby deforming the clip into the closed positionshown in FIG. 8B. Distal extremity 114 is driven in a generallyrotational manner about an axis located roughly at the junction betweenproximal extremity 116 and clip body 112. Recess 138 is configured toallow distal extremity 114 to be moved completely into the closedposition without interference with inner shaft 134. After closure, clipcover 144 may be retracted away from holding mechanism 136 and clip 110then released from pin 140.

Still another embodiment of a surgical clip according to the inventionis illustrated in FIGS. 9A-9B. Surgical clip 150 includes a proximalextremity 152 and a distal extremity 154. Distal extremity 154 has asharp distal point 160 for penetrating tissue. Proximal extremity 152includes an aperture 162 to facilitate holding clip 150 in a clipapplier, as described below. Distal extremity 154 is movable between theopen position of FIG. 9A and the closed position of FIG. 9B. A notch 155is disposed at the junction of the distal and proximal extremities whichcauses distal extremity 154 to pivot in a hinge-like manner about anaxis passing generally through the base of the notch when a transverseforce is applied to distal extremity 154. Clip 150 is preferably made ofa deformable metal so as to remain in the closed position when closureforce is released. Distal extremity 154 has an inner surface 156 whichfaces an outer surface 158 of proximal extremity 152. In the closedposition, at a point adjacent to the junction of the distal and proximalextremities, inner surface 156 is preferably separated from outersurface 158 by less than the combined thickness of the tissue layers towhich clip 150 is to be applied, so as to compress the tissue betweenthe distal and proximal extremities. It is most preferred that notch 155be configured to allow the edges of the tissue to reside within thenotch, such that when the clip is closed, the layers of tissue will becompressed within the notch itself.

A distal portion of an applier 164 for closing clip 150 is illustratedin FIGS. 10A-10D. Applier 164 includes an outer shaft 166 having a lumen168, and an inner shaft 170 over which outer shaft 166 is slidable. Anactuator handle like that described above in connection with FIGS. 2A-2Cis attached to the proximal end of inner shaft 170 and coupled to outershaft 166 such that actuation of the handle moves outer shaft 166proximally relative to inner shaft 170. Thus, for this embodiment, links66 of FIGS. 2A-2C will be oriented such that the outer ends pinned toleaves 66 are distal to the inner ends pinned to outer shaft 166,thereby pulling the outer shaft proximally when the leaves are pivotedinwardly. In this embodiment, outer shaft 166 is rotatably mounted tocollar 67 so as to be rotatable relative to inner shaft 170 for reasonswhich will become apparent below.

A clip holding mechanism 172 is attached to the distal end of innershaft 170 and includes a pair of transverse pins 174 over which clip 150may be placed. A clip cover 176 is slidably mounted in parallel to adistal portion of inner shaft 170 and is biased distally by a spring 178disposed within lumen 168 which engages the proximal end of the clipcover. In this way, after a clip is placed on pins 174 with clip cover176 in the retracted position shown, clip cover 176 is allowed to returnto a distal position covering proximal extremity 152 of the clip so asto retain it on pins 174.

An anvil 180 extends distally from a distal end of outer shaft 166 andhas a transverse end 182 generally orthogonal to a longitudinal axis ofthe outer shaft (and generally parallel to the axis of movement ofdistal extremity 154). In order to facilitate penetrating distalextremity 154 through the tissue to which the clip is to be applied,anvil 180 is initially positioned proximally of distal extremity 154 asshown in FIG. 10A by maintaining leaves Alternatively, anvil 180 itselfmay be mounted to outer shaft 166 so as to be pivotable or rotatable toa position suitably distant from distal extremity 154. Anvil 180 ispositioned so that transverse end 182 may be positioned distally of andgenerally perpendicular to distal extremity of 154 of the clip, asillustrated in FIGS. 10A-10B. In this way, when the actuator handle ofapplier 164 is actuated, transverse end 182 is drawn in the proximaldirection, engaging distal extremity 154 and deforming it into theclosed position shown in FIG. 10C.

A surgical clip system according to the invention is illustrated inFIGS. 11A-11B. Clip system 190 includes plurality of clips 192 coupledto a flexible band 194. Clips 192 include, as shown in FIG. 12A, aproximal extremity 195, a needle portion 196 having a sharp distal point198 for penetrating tissue, and a coupling 200 for attachment to band194. Needle portion 196 is preferably curved or J-shaped with its distalend being at an angle of no more than about 90, and preferably about45-85 relative to proximal extremity 195. Preferably, coupling 200comprises a loop, eyelet, or other structure through which band 194 maybe inserted that allows clip 192 to slide along band 194. Alternatively,coupling 200 may be configured to non-movably attach clip 192 to theband, such as by clamping or crimping onto the band, by bonding orwelding the coupling to the band, or by allowing the band to be knottedor looped through the coupling. Needle portion 196 preferably includes abarb 202 which prevents the needle portion from being removed from thetissue to which it is applied.

Band 194 is a flexible biocompatible material such as suture or anelastomeric or metallic strap, band or cable. Band 194 is preferably acontinuous annular ring, but may also be a non-continuous or broken ringbiased into a generally annular shape, with a retainer on each end toretain clips 192 on the band. Usually the shape of band 194 will becircular, but could alternatively be a variety of other non-circularshapes including elliptical, egg-shaped, cobra head-shaped, oval, or thelike. In any case, the flexibility of the band allows it to conform towhatever shape is desirable for the particular vascular structures withwhich it is being used. Clips 192 may be mounted to band 194 with theall needle portions 196 pointing outward as shown, or with some ofneedle portions 196 pointing inward. As shown in FIG. 11B, clips 192 mayalso be attached to band 194 so that some extend upward from the band,while others extend downward from the band.

FIGS. 12B-12G illustrate various alternative embodiments of clips foruse in clip system 190. In FIG. 12B, a length of hypotube 204 is mountedover proximal extremity 195B. A hole 206 is disposed near the proximalend of hypotube 204 through which band 194 may be inserted. The distalend 208 of hypotube 204 engages the tissue through which needle portion196B is inserted and prevents its movement upward along proximalextremity 195B. Preferably, the length of hypotube 204 is selected sothat the distance between distal end 208 and barb 202B is less than thecombined thickness of the tissue layers through which needle portion196B is inserted so that the tissue is compressed between the hypotubeand the barb.

In FIG. 12C, clip 192C has a plurality of barbs 210 arrangedsequentially along needle portion 196C. A stop 212 is disposed onproximal extremity 195C. In this way, the layers of tissue to which clip192C is applied may be translated along needle portion 196C until theouter layer contacts stop 212. Barbs 210 prevent the tissue from movingaway from stop 212. Preferably, the distance between stop 212 and barbs210 is less than the combined thickness of the tissue to allow thetissue to be compressed between the stop and the barbs.

In FIG. 12D, clip 192D has a configuration like clip 192 of FIG. 12A,but in this embodiment the clip is constructed of a shape memory alloysuch as Nitinol (Raychem Corp.). At body temperature the clip has aclosed shape in which distal point 198D is close to or contactingproximal extremity 195D so as to define an enclosed space in which thetissue is retained. The clip may be isothermally transformed from anopen to a closed shape by using needle drivers or other suitableinstruments to hold distal point 198D away from proximal extremity 195Dthen release the distal point after it has been applied to tissue.Preferably, however, the clip is thermally transformed by heating theclip to the material's transition temperature using a heated probe orneedle driver until the clip assumes the closed shape.

In FIG. 12E, clip 192E has a hypotube 214 mounted to proximal extremity195E as in FIG. 12B, and includes a retainer 216 mounted to proximalextremity 195E which abuts the distal end of hypotube 214. A distalretainer 218 is threadably or slidably received over needle portion 196Ewhich may be placed on the needle portion after it has been applied tothe tissue. The tissue may be advanced along needle portion 196E untilit engages retainer 216, and distal retainer 218 then moved into contactwith the opposing side of the tissue to compress it between the tworetainers.

In FIGS. 12F-G, clip 192F has a pair of opposing needle portions 220A,220B connected by a bridging segment 222. Bridging segment 222 mayinclude a loop 224 which enhances deflection of needle portions 220.Clip 192F is movable from the open configuration of FIG. 12F to theclosed configuration of FIG. 12G wherein needle portion 220A, 220B crossover one another to define an enclosed space in which the tissue may beretained. Preferably, clip 192F is made of a superelastic shape memoryalloy such as Nitinol. In one embodiment, the clip is biased into theclosed configuration at ambient and body temperature, and isisothermally held open using appropriate instruments to apply needleportions 220 to the target tissue, then released to allow the clip toclose. In an alternative embodiment, the material has a transitiontemperature above ambient temperature at which it resumes the closedshape from the open shape. In this way, after clip 192F has been appliedto tissue in the open configuration, heat may be applied to the clipusing a heating probe or heated forceps to cause it to assume the closedconfiguration.

It should be understood that the embodiments illustrated in FIGS.12A-12G are only exemplary of the wide variety of clips that may be usedin the surgical clip system of the invention. Moreover, any of the clipsillustrated in FIGS. 1-10 above may be used in clip system 190 of FIGS.11A-11B by, for example, providing an additional aperture in the clipbody through which band 194 may extend.

FIGS. 13A-13C illustrate the use of clip system 190 in the anastomosisof a graft vessel G to a target vessel T. Initially, band 194 to whichclips 192 are coupled is placed over the end GE of graft vessel G.Vessel end GE is then everted over clips 192 to allow each needleportion 196 to penetrate the graft vessel wall from the exterior surfaceof the vessel toward the interior surface (which now faces outwardly) asshown in FIG. 13B. Clips 192 may be repositioned along band 194 asneeded to allow selection of the optimum location at which each needleportion 196 penetrates the graft vessel wall based on the shape andcondition of the vessel. An opening O is formed in the target vesselwall corresponding to the size and shape of everted graft vessel end GEusing a surgical knife or scissors. Everted graft vessel end GE is theninserted into opening O and the edges of vessel end GE are approximatedwith the edges of opening O. Each needle portion 196 is then graspedwith surgical needle drivers or forceps and penetrated through the wallof target vessel T from the interior toward the exterior thereof. Theautonomy of each clip 192, the flexibility of band 194 and thecompliance of graft vessel G allow each clip 192 to be manipulated andpositioned to penetrate the target vessel wall at the optimum locationaccording to the shape and condition of the vessel. Needle portions 196are inserted through the target vessel wall until barbs 202 pass throughto the exterior of the vessel. The vessel walls are thus compressedbetween barbs 202 and proximal extremities 195, providing a secure andhemostatic connection. Optionally, band 194 may then be severed andremoved from clip couplings 200. This ensures that each clip iscompletely autonomous and unrestricted by the other clips, providing acompliant anastomosis comparable to a sutured anastomosis.

An additional embodiment of a surgical clip according to the inventionis illustrated in FIGS. 14A-14C. In this embodiment, surgical clip 230may be formed by cutting out a two-dimensional pattern from a flat pieceof material as shown in FIG. 14B, making the clip more simple andeconomical to manufacture. Clip 230 has a distal extremity 232, aproximal extremity 234, and a flanged central portion 236 therebetweenwhich has a transverse width substantially wider than the distalextremity. Distal extremity 232 has a distal point 233 configured topenetrate tissue. Proximal extremity 234 is bifurcated into twospaced-apart segments 238 defining an opening 240 therebetween in whichdistal extremity 232 may be received in the closed position of FIG. 14C.Distal extremity 232 is disposed at an angle of about 30°-120°,preferably about 60°-120°, relative to flanged central portion 236.Proximal extremity 234 is preferably at an angle of at least about 90°relative to flanged central portion 236 to facilitate closure of theclip in the manner described below.

Flanged central portion 236 is configured to be held by an applier 242,illustrated in FIGS. 15A-15C. Applier 242 is preferably adapted forholding a plurality of clips 230 simultaneously and automaticallyfeeding and applying the clips in succession. Applier 242 has an innershaft 244 having a distal end 246, a proximal end 248 and a lumen 250therebetween. An actuator 252 is mounted to the proximal end 248, andhas a pair of pivotable leaves 254 extending distally and outwardlytherefrom. An outer shaft 256 is slidably disposed over inner shaft 244and has a distal end 258 and a proximal end 260. A pair of links 262 arepinned at their outer ends to leaves 254 and at their inner ends to acollar 263 attached to proximal end 260 of outer tube 256. In this way,when the user pivots leaves 254 inwardly, outer shaft 256 is translateddistally relative to inner shaft 244. A flat spring (not shown) may bemounted to leaves 254 to bias them in the outward position, or a tensionspring (not shown) may be mounted to outer shaft 256 to bias it in theproximal direction.

Inner shaft 244 has an axial channel 266 along one side of inner lumen250 configured to slidably receive a plurality of clips 230. Asillustrated in FIG. 15B, channel 266 has a width wide enough to receiveflanged central portions 236 of clips 230. A wall 268 separates channel266 from lumen 250 and has a slot 270 narrower than flanged centralportions 236, but wide enough to allow distal extremities 232 andproximal extremities 234 to slide axially. In this way, a plurality ofclips 230 may be lined up end to end in channel 266, with the distalextremity of each clip abutting the proximal extremity of an adjacentclip. A pusher 272 is mounted to the proximal end of inner shaft 244 andis biased distally by spring 274. Pusher 272 has a distal end 276configured to push against the most proximal clip in channel 266,thereby urging all of clips 230 toward distal end 246.

Channel 266 is angled laterally as it approaches distal end 246, andterminates at an abutment 278 against which the distal most clip 230′ ispositioned. This exposes most of distal extremity 232′ to facilitateapplying it to one or more layers of tissue, and positions proximalextremity 234′ adjacent to distal end 258 of outer shaft 256. In thisway, when actuator 252 is actuated, outer shaft 256 engages proximalextremity 234′ of clip 230′ and urges it into the closed position ofFIG. 14C. As shown in FIG. 15C, slot 270 widens at the distal end ofchannel 266 to a width wider than flanged central portion 236′, allowingclip 230′ to be withdrawn from channel 266 after it has been closed.When clip 230′ has been withdrawn, the next clip in line is urgeddistally by pusher 272 until it contacts abutment 278, where it is readyfor application. Thus, a plurality of clips may be applied successivelyto a surgical site within a body cavity without removing the applierfrom the body cavity to reload clips.

Clip applier 242 may be preloaded with a plurality of clips 230 anddisposed of upon application of all of the clips. Alternatively, innershaft 244 may be detachable from actuator 252, allowing the actuator andouter shaft to be sterilizable and reusable, with inner shaft 244 beingreplaced or reloaded with clips between uses. In addition, clip applier242 is preferably configured for endoscopic uses, having a length andprofile suitable for positioning through a trocar sleeve or other smallpercutaneous access port into a body cavity.

While the above is a complete description of the preferred embodimentsof the invention, various alternatives, substitutions, modifications,and equivalents of the embodiments described are possible withoutdeparting from the principles thereof. Therefore, nothing disclosedabove should be taken to limit the scope of the invention, which isdefined by the appended claims.

1. A method of forming an anastomosis by placing a lumen of a graftvessel in fluid communication with a lumen of a target vessel through anopening in a wall of the target vessel, comprising the steps of:providing a plurality of clips, the clips being made of superelasticmaterial, each of the plurality of clips each having a first end and asecond end, a first configuration, where the first end and second endare spaced apart so as to be able to receive therebetween a portion ofthe graft vessel and a portion of a target vessel tissue proximate theopening in the wall of the target vessel, and a second configuration,where the portion of the graft vessel and the portion of the targetvessel are approximated; positioning the first end of each of theplurality of clips through the opening in the target vessel; passing thefirst end of each of the plurality of clips through an inner wall of thetarget vessel while the clips are in the first configuration; passing atleast a portion of each of the plurality of clips through the graftvessel; and permitting each of the plurality of clips to assume thesecond position to approximate the graft vessel and the target vessel.2. The method of claim 1, wherein the second passing step comprisespassing the first end of each of the plurality of clips through an outerwall of the graft vessel.
 3. The method of claim 2, wherein the secondpassing step occurs prior to the positioning step.
 4. The method ofclaim 1, comprising the step of positioning one end of each clip throughthe graft vessel at radially spaced locations about the graft vessel. 5.The method of claim 1, wherein each clip of the plurality of clips isseparately passed through the graft vessel.
 6. The method of claim 1,comprising compressing the graft vessel and the target vessel togetherwhen at least one of the plurality of clips is in the secondconfiguration.
 7. The method of claim 1, wherein each clip of theplurality of clips independently approximates the graft vessel and thetarget vessel when each clip of the plurality of clips is in the secondconfiguration.
 8. The method of claim 1, wherein at least one of thefirst end and the second end of the plurality of clips cross over oneanother when moving from the first configuration to the secondconfiguration to form an enclosed space to retain a portion of the graftvessel and a portion of the target vessel.
 9. The method of claim 1,wherein each clip is isothermally transformed from the firstconfiguration to the second configuration.
 10. The method of claim 1,wherein each clip of the plurality of clips is restrained in the firstconfiguration.
 11. The method of claim 1, comprising, prior to thepermitting step, releasing each clip of the plurality of clips from thefirst configuration.
 12. The method of claim 11, wherein the releasingstep is performed using one of a needle driver and forceps.
 13. A methodof forming an anastomosis by placing a lumen of a graft vessel in fluidcommunication with a lumen of a target vessel through an opening in awall of the target vessel, comprising the steps of: providing aplurality of clips, the clips being made of superelastic material, eachof the plurality of clips each having a first end and a second end, afirst configuration, where the first end and second end are spaced apartto receive therebetween a portion of the graft vessel and a portion of atarget vessel tissue proximate the opening in the wall of the targetvessel, and a second configuration, where the portion of the graftvessel and the portion of the target vessel are approximated; couplingeach of the plurality of clips to a band; passing each of the pluralityof clips through the graft vessel and the target vessel; and permittingeach of the plurality of clips to assume the second configuration toapproximate the graft vessel and the target vessel.
 14. The method ofclaim 13, comprising the step of severing the band.
 15. The method ofclaim 14, comprising the step of removing the band from each of theplurality of clips.